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Abstract:

A trailer light tester for supplying DC current to at least one circuit
in a trailer where a seven pin female connector is rigidly and securely
attached to a side or rear panel of the trailer light tester wherein,
when the seven pin female connector which is rigidly and securely
attached to the light tester is connected to the seven pin male connector
which is rigidly and securely attached to the front end of the body of a
truck trailer, the light tester is rigidly and securely attached to and
is fully supported by the seven pin connector attached to the body of the
truck trailer and projects out from the front end of the truck trailer
body without requiring any additional support.

Claims:

1. A trailer light tester for supplying DC current to at least one
circuit in a trailer comprising: a seven pin female connector rigidly and
securely attached to a side or rear panel of the trailer light tester;
and a seven pin male connector rigidly and securely attached to the front
end of the body of the trailer; wherein when the seven pin female
connector which is rigidly and securely attached to the light tester is
connected to the seven pin male connector rigidly and securely attached
to the body of a truck trailer, the light tester is rigidly and securely
attached to and is fully supported by the body of the truck trailer and
projects out from the front end of the truck trailer body without
requiring any additional support.

2. The trailer light tester of claim 1 further comprising: a rechargeable
battery located within the light tester for supplying DC current through
a first switch to a first turn indicator circuit in the trailer having at
least one bulb; and a flasher coupled in series to the first switch.

3. The trailer light tester of claim 2 wherein the flasher is an LED
flasher.

4. The trailer light tester of claim 3 wherein the bulbs in the flasher
are LED bulbs.

5. The trailer light tester of claim 4 further comprising a second switch
for feeding current through a second LED flasher to a second turn
indicator circuit in the trailer having at least one bulb.

6. The trailer light tester of claim 5 wherein the at least one bulb in
the second turn indicator circuit is an LED bulb.

7. The trailer light tester of claim 6 wherein the first and second
switches are single throw single pole switches.

8. The trailer light tester of claim 7 wherein a fusible link is coupled
in series with the first switch and the second switch.

9. The trailer light tester of claim 8 further comprising a third switch
for feeding current from the rechargeable battery to an auxiliary circuit
wherein the auxiliary circuit is a circuit for oversize flashing lights,
valves to dump air from moveable axles or valves to pull pins from
extendable trailers.

10. The trailer light tester of claim 9 wherein a fusible link is coupled
in series with the third switch.

11. The trailer light tester of claim 10 wherein the third switch is a
single throw single pole switch.

12. The trailer light tester of claim 11 further comprising a fourth
switch for feeding current from the rechargeable battery to a tail light
and side marker circuit on the trailer.

13. The trailer light tester of claim 12 wherein a fusible link is
coupled in series with the fourth switch.

14. The trailer light tester of claim 13 wherein the fourth switch is a
single throw single pole switch.

15. The trailer light tester of claim 14 further comprising a fifth
switch for feeding current from the rechargeable battery to a brake
circuit on the trailer.

16. The trailer light tester of claim 15 wherein a fusible link is
coupled in series with the fifth switch.

17. The trailer light tester of claim 16 wherein the fifth switch is a
single throw single pole switch.

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to a portable apparatus for
testing electrical circuits and, more specifically, relates to apparatus
for testing the continuity of circuits and operation of incandescent and
LED bulbs and turn signals on trailers used for long distance hauling in
the tractor trailer industry.

[0003] 2. Description of Related Art

[0004] Large cross country trailers which are pulled by tractors capable
of carrying 60,000 pounds or more of merchandise have a plurality of
separate electrical lighting circuits which go from the front to the rear
of the trailer. For example, the various circuits include marker lights
which are located around the sides of the trailer, stop lights located at
the rear of the trailer, left and right turn signal lights which are
located at the rear of the trailer and, in some instances, on the sides
of the trailer. It is necessary that each of these circuits and the light
bulbs, whether they are incandescent light bulbs or LED light bulbs, are
always operational to satisfy the various state and local safety
requirements and the safety of the general public.

[0005] Therefore, before a trailer is connected to a tractor for a trip to
a distant destination, the various lighting circuits, including the
bulbs, are tested to make sure that they are in proper working condition.
However, trailers normally do not carry their own batteries and may rely
on a tractor to which it is connected to supply the power needed to
operate the various circuit and light bulbs. In practice, the circuit and
bulb testing procedure is performed at a trucking yard or terminal either
while the trailer is connected to a tractor or a tractor is backed up and
connected to the trailer just to test the various circuits by using the
battery in the tractor as a source of power and the switches and brakes
of the tractor to operate the various circuits.

[0006] Testing apparatus which provides self-contained switching circuits
and power sources which can be connected to a trailer to test the various
circuits and bulbs on a trailer is known in the prior art. More
specifically, by way of example, U.S. Pat. No. 6,674,288 to Gumbel, et
al. discloses a vehicle which provides the automatic activation and
deactivation of the lights in a predetermined sequence upon user request
to assist the user in making a sight inspection of the operation of the
lights without further human help.

[0007] U.S. Pat. No. 6,265,878 to Traub discloses testing the circuits on
a trailer without a tractor being connected thereto. A digital signal
which is different for each device to be tested is encoded and wirelessly
transmitted. Upon receipt of the signal, a power source is connected to
the respective device to be tested. In order to reliably apply the signal
in a multiplexed system in the trailer, the signal is mixed with a
pseudorandom digital sequence to provide a direct sequence spread
spectrum for the signal.

[0008] U.S. Pat. No. 6,172,508 to Nutt discloses a housing having a front
control panel, a pair of battery terminals connected to the housing for
connecting it to a battery and a cable connected to the housing having a
connector which can be connected to an electrical receptacle of a
trailer. A plurality of switches are connected to the battery and the
connector for testing various electrical circuits in the trailer.

[0009] U.S. Pat. No. 6,081,189 to Warner discloses a battery and a flasher
component electrically connected to a positive terminal of the battery. A
switch is electrically connected to the flasher component and an
indicator light is associated with a respective trailer light. The switch
is selectively opened to de-energize the positive conductor and closed to
energize the positive conductor. Attaching the harness to the lighting
circuit connector component and closing the switch causes the indicator
light to flash intermittently when the trailer light, positive wire and
ground wire are operative and glow continuously when at least one of the
trailer light, positive wire and ground wire is inoperative.

[0010] U.S. Pat. No. 5,602,482 to Gutierrez discloses a portable device
for checking electrical signaling systems of trailers. An electrical
circuit includes switches for energizing individual signaling circuits of
the trailer individually, and indicating lamps for annunciating circuit
operability. The device, which is contained on a wheeled cart, has its
own power supply and circuit overcurrent protective devices, and is thus
independent of a tractor which normally generates the signals.

[0011] U.S. Pat. No. 5,416,421 to Doland, Sr., et al. discloses a lamp
testing apparatus having a predetermined number of battery-powered
testing circuits and a connector assembly for receiving respective ends
of the predetermined number of testing circuits. Lamp circuits in the
trailer are placed in series with corresponding testing circuits in the
testing circuitry assembly, whereby lamps in the trailer are capable of
being tested by the testing circuits in the testing circuit assembly.

[0012] U.S. Pat. No. 4,884,032 to LaPensee discloses a portable testing
mechanism for tractor-trailer lighting systems which permits a test of
the trailer lighting system without the physical presence of the tractor,
or to permit test of a tractor light control system without the physical
presence of the trailer.

[0013] U.S. Pat. No. 4,866,390 to Butchko discloses an arrangement for
scanning the plurality of lights in a predetermined scanning sequence.
This scanning allows a single operator to check the different operating
functions of the lights in a single trip around the vehicle. Thus, the
scanning sequence can progress from the left turn signal to the brake
lights to the right turn signal (and then repeat the cycle again) so that
an operator in the back of the vehicle can watch the lights progress
through this sequence.

[0014] U.S. Pat. No. 4,547,722 to Sarlo discloses a testing unit for
testing the lighting of truck tractors and trailers wherein the tester
can be alternately connected to the truck or the tractor and, when
connected to the tractor, a battery in the tester provides power to
energize the various circuits in the trailer. When the tester is
connected to the trailer, various accessories on the tractor are turned
on and the indicator lights on the tester will light and correspond to
the accessories turned on in the tractor.

[0015] U.S. Pat. No. 3,737,767 to Slutsky discloses a portable apparatus
which is operable from a battery, and includes a chassis having a
plurality of switches for actuating the circuits being tested.

SUMMARY OF THE INVENTION

[0016] In an exemplary embodiment of the present invention, there is
disclosed a trailer light tester for supplying DC current to at least one
circuit in a trailer where a seven pin female connector is rigidly and
securely attached to a side or rear panel of the trailer light tester
wherein, when the seven pin female connector which is rigidly and
securely attached to the light tester is connected to the seven pin male
connector which is rigidly and securely attached to the front end of the
body of a truck trailer, the light tester is rigidly and securely
attached to and is fully supported by the seven pin connector attached to
the body of the truck trailer and projects out from the front end of the
truck trailer body without requiring any additional support.

[0017] The more important features of the invention have thus been
outlined in order that the more detailed description that follows may be
better understood and in order that the present contribution to the art
may better be appreciated. Additional features of the invention will be
described hereinafter and will form the subject matter of the claims that
follow.

[0018] Before explaining at least one embodiment of the invention in
detail, it is to be understood that the invention is not limited in its
application to the details of construction and the arrangements of the
components set forth in the following description or illustrated in the
drawings. The invention is capable of other embodiments and of being
practiced and carried out in various ways. Also it is to be understood
that the phraseology and terminology employed herein are for the purpose
of description and should not be regarded as limiting.

[0019] As such, those skilled in the art will appreciate that the
conception, upon which this disclosure is based, may readily be utilized
as a basis for the designing of other structures, methods and systems for
carrying out the several purposes of the present invention. It is
important, therefore, that the claims be regarded as including such
equivalent constructions insofar as they do not depart from the spirit
and scope of the present invention.

[0020] The foregoing has outlined, rather broadly, the preferred feature
of the present invention so that those skilled in the art may better
understand the detailed description of the invention that follows.
Additional features of the invention will be described hereinafter that
form the subject of the claims of the invention. Those skilled in the art
should appreciate that they can readily use the disclosed conception and
specific embodiment as a basis for designing or modifying other
structures for carrying out the same purposes of the present invention
and that such other structures do not depart from the spirit and scope of
the invention in its broadest form.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other aspects, features, and advantages of the present invention
will become more fully apparent from the following detailed description,
the appended claim, and the accompanying drawings in which similar
elements are given similar reference numerals.

[0022] FIG. 1 is perspective view of a truck trailer light tester here
disclosed which is rigidly and securely attached to a seven pin
connector. When the seven pin connector on the light tester is connected
to a seven pin connector that is rigidly and securely attached to the
body of a truck trailer, the light tester is rigidly attached to and is
supported by the body of the truck trailer and projects out from the
front end of the truck trailer without any additional support;

[0023]FIG. 2 is a perspective view of the front panel of the truck
trailer light tester showing a partial view of the seven pin connector
extending out of the right hand end of the light tester; and

[0024] FIG. 3 is a schematic wiring diagram of the truck trailer light
tester in accordance with the principles of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0025] Annual or periodic testing of the various lighting circuits on a
trailer to insure that they are operating properly is mandatory in many
states and localities. Normally the testing of the lighting circuits is
done by a truck mechanic while performing regular periodic maintenance on
the tractor and trailer such as inspecting the brakes, tires, oil level,
etc. Typically, while in the cab of the tractor, the mechanic will turn
on the turn signals, marker lights, step on the break to check the brake
lights, etc. and, after each operation, walk around the trailer to see if
all the lights are working. Clearly, a time consuming process which can
be done much faster if a second mechanic is available to help with the
testing procedure.

[0026] Referring to FIG. 1, there is disclosed a perspective view of a
truck trailer light tester rigidly and securely attached to a seven pin
female connector. When the seven pin female connector on the light tester
is connected to the seven pin male connector that is rigidly attached to
the front of the body of a truck trailer, the light tester is rigidly
attached to and is supported by the body of the truck trailer. The light
tester projects out from the front end of the truck trailer body without
requiring any additional support.

[0027] The detailed description of the preferred embodiment of the
invention relates to the testing of lighting circuits and bulbs on
trailers which are hauled to distant locations over the interstate
highway system by tractors. It is understood, however, that this
invention is not limited to testing lighting circuits and bulbs on
highway trailers, but may be used, for example, to test the lighting
circuits of fleet rental cars, company cars, buses, etc. by simply adding
an external socket which is attached to the body of the rental car,
company car or bus which is connected to the lighting circuits of the
vehicle that is to be tested.

[0028] Looking at FIG. 1, a trailer light testing apparatus 10 which
contains its own source of twelve volt DC power or may be connected to a
source of power such as a twelve volt rechargeable battery, is
electrically connected through a seven prong female connector 14 (See
FIG. 2) securely and rigidly attached to the light tester 10 to the
lighting circuits on a trailer 16 through a seven prong male connector
securely and rigidly connected to the body of a trailer.

[0029] While the number of prongs that are present in the connector is
optional, the connector used with this invention has seven prongs because
that is the standard connector that is currently being used on all
trailers for providing power between the tractor and each of the lighting
circuits on the trailer.

[0030] Referring to FIG. 2, there is shown a perspective view of the front
panel of the trailer light tester apparatus where a seven pin female
connector 14 is rigidly and securely attached to a side panel of the
trailer light tester apparatus 10. Power is supplied to the trailer light
tester apparatus from a battery which is located within the trailer light
tester or may be external to and electrically connected to the trailer
light tester 10 which is then selectively fed to the various lighting
circuits in the trailer 16 through the female and male sections of the
seven prong connector which are securely and rigidly connected to the
trailer light tester and the body of the trailer.

[0031] The front panel 20 of the trailer light tester has five single pole
single throw switches 22, 24, 26, 28, and 30 the functions of which are
more fully identified as follows. Switch 22, left turn indicator lights;
switch 24, auxiliary lights; switch 26, tail lights and marker lights;
switch 28, stoplights; and switch 30, right turn lights. Following
standard procedures, the switches are positioned on the front panel to be
flipped either up or down where a switch is in its conducting state when
it is in its up position and is in its open or non-conduction state when
in its down position. If desired, light emitting diodes can be located on
the front panel next to each switch to visually indicate to a user if the
switch is in its conducting or non-conducting state.

[0032] Referring to FIG. 3, there is shown a schematic wiring diagram of
the truck trailer light tester apparatus in accordance with the
principles of the invention. The tester 10 contains it own twelve volt
rechargeable battery supply 12 which is adapted to be connected to a
power supply cable 34 located within the tester which has a positive clip
for attachment to the positive terminal of the twelve volt battery 12 and
a ground or negative clip for attachment to the negative terminal of the
battery 12. Power from the battery is controllably and selectively
directed through the trailer light testing control panel 10 to a seven
prong female connector 14 which is connected to ground and is rigidly and
securely attached to the enclosure which is used to house the electrical
circuit tester 10.

[0033] For purposes of convenience only and not intended to identify an
actual pin of the connector that is connected to a specific circuit, the
pins are identified with letters where, for the purposes of explanation
only, pin A is the pin connector for the marker lights; pin B is the pin
connector for the left turn circuit indicator lights; pin C is the pin
connector for the stop lights; pin D is the pin connector for the right
turn circuit indicator lights; pin E is the pin connector for the tail
lights, pin F is the pin connector for the auxiliary systems circuit, and
pin H is the pin connector that is connected to a ground and to the
negative terminal of the twelve volt battery.

[0034] Referring now to the circuit of the trailer light testing apparatus
10, the positive battery terminal is connected to a fixed contact of a
single throw single pole switch 22 for the left turn indicator light
circuit, to a fixed contact of a single pole single throw switch 24 for
the auxiliary light circuit, to a fixed contact of a single pole single
throw switch 26 for the marker and tail light circuits, to a fixed
contact of a single pole single throw switch 28 for the stop light
circuit, and to a fixed contact of a single pole single throw switch 30
for the right turn indicator light circuit.

[0035] Movable contact of switch 30 is connected through fusible link 40
to the X terminal of twelve volt LED flasher 42. The L terminal of
flasher 42 is connected to pin B of the seven pin connector which is the
left turn indicator light circuit. Movable contact of switch 24 is
connected through fusible link 44 to pin F of the seven pin connector
which is the auxiliary circuit, of the trailer. The auxiliary circuit may
be a circuit for different applications, oversize flashing lights, valves
to dump air from moveable axles, valves to pull pins from extendable
trailers, etc. Movable contact of switch 26 is connected through fusible
link 46 to pins A and E of the seven pin connector which are the marker
and tail light circuits of the trailer. Movable contact of switch 28 is
connected through fusible link 48 to pin C of the seven pin connector
which is the stop light circuit of the trailer. Movable contact of switch
30 is connected through fusible link 50 to the X terminal of a twelve
volt LED flasher 52. The L terminal of flasher 52 is connected to pin D
of the seven pin connector which is the right turn indicator light
circuit of the trailer.

[0036] In an embodiment of the invention, the LED flashers 42, 52 may be
connected in parallel with a current limiting circuit having a single
throw single pole toggle switch to allow the LED flashers to be used with
turn indicators which have either LED bulbs or incandescent bulbs. The
current limiting circuit is connected across the LED flasher to limit the
current only through the LED flasher but not to the bulbs when the bulbs
in the turn indicator are incandescent by by-passing the excess current
around the LED flasher. When the bulbs of the turn indicator are LED
bulbs, the current limiting circuit allows the full current to pass
through the LED flasher. Thus, when the turn indicators have incandescent
bulbs, the current limiting circuit will only limit the current through
the LED flasher but not the amount of current to the bulbs. When the turn
indicators have LED bulbs, the current limiting circuit will not limit
the current through the LED flasher.

[0037] While there have been shown and described and pointed out the
fundamental novel features of the invention as applied to the preferred
embodiments, it will be understood that the foregoing is considered as
illustrative only of the principles of the invention and not intended to
be exhaustive or to limit the invention to the precise forms disclosed.
Obvious modifications or variations are possible in light of the above
teachings. The embodiments discussed were chosen and described to provide
the best illustration of the principles of the invention and its
practical application to enable one of ordinary skill in the art to
utilize the invention in various embodiments and with various
modifications as are suited to the particular use contemplated All such
modifications and variations are within the scope of the invention as
determined by the appended claims when interpreted in accordance with the
breadth to which they are entitled.